1. Field of the Invention
The present invention relates to a liquid crystal display panel having two liquid crystal layers and a color layer and affording a multi-color display.
2. Description of the Related Art
U.S. Pat. No. 4,886,343 discloses a liquid crystal display device utilizing additive and subtractive color integrating techniques. In this prior art, the liquid crystal display device comprises two superposed liquid crystal display panels, and is used with a color filter to provide a multi-color display. The color filter has two color regions within one picture element, and a plurality of colors are presented by an additive color integration by selectively using one or both of the color regions. Also, each of the liquid crystal panels comprises a liquid crystal containing a dichroic dye having a particular color, and a plurality of colors are presented by a subtractive color integration by selectively using one or both of the colors of the two liquid crystal layers; for example, three colors, i.e., the color of dichroic dye in the first liquid crystal panel, the color of dichroic dye in the second liquid crystal panel, and the color of superposed liquid crystal panels, can be produced. In addition, further colors are produced by superposing the colors of the color filter and the color of the liquid crystal panels.
The liquid crystal panel typically comprises a pair of glass plates and a layer of liquid crystal inserted between the glass plates. When two liquid crystal display panels are used, the composite arrangement comprises a layer of liquid crystal inserted between a pair of glass plates and another layer of liquid crystal inserted between another pair of glass plates. However, in the arrangement including two superposed liquid crystal display panels, it is possible to omit one of the intermediately located glass plates. Thus, the liquid crystal display device of the above described prior art comprises a first outer glass plate (a color filter plate), an intermediately located glass plate, a second outer glass plate, a first layer of liquid crystal inserted between the color filter plate and the intermediately located glass plate, and a second layer of liquid crystal inserted between the intermediately located glass plate and the second outer glass plate.
In the liquid crystal display device including two superposed liquid crystal display panels, there is an intermediately located glass plate between two layers of liquid crystal. Generally, the thickness of the glass plate is considerably thicker than the thickness of the second layer of liquid crystal. Therefore, when a light is obliquely incident to the intermediately located glass plate and passes through the intermediately located glass plate, the position of the light emerging from the intermediately located glass plate is shifted laterally along the plate relative to the position of the light incident to the intermediately located glass plate. In addition, the areas of the picture elements are small, particularly in high definition display devices. Therefore, a problem arises in that when a light is obliquely incident to a certain picture element, the light may emerge from the adjacent picture element. The light may leak into the black display area and the contrast may be reduced.